Color radiography



United States Patent C) 2,994,610 COLOR RADIOGRAPHY Fritz Mans, Koln-Dentz', Germany, assignor to Agfa Aktiengesellschaft No Drawing. Filed Sept. 4, 1957, Ser. No. 681,892 Claims priority, application Germany Sept. 26, 1956 2 Claims. (Cl. 96-100) This invention is concerned with color radiography and more espectially relates to the production of color radiographs having different color shades in the shadows and in the high lights.

Numerous measures are already known for increasing the contrast of X-ray photographs or for improving the definition of detail, such as for example the use of X-rays of different hardness, emulsions of different gradations or intensified foils of different fluorescence, and in the last-mentioned case the photographic layers are adapted to different types of fluorescence.

Furthermore, it has been proposed to produce multicolor X-ray photographs on multi-layer material, different X-ray ranges being associated with individual layers by using for example absorption means for certain wavelengths. Furthermore, it is known that the definition of detail can be improved if provision is made, by suitable production of dyes, for the color tone to be additionally modified with increasing density of the image. In this process, the modification of the color tone or of the color trends is produced by using emulsions with different sensitivity and gradation for each color, so that the change in the image color is obtained by overlapping of the gradation curves for the different colors. The use of this material for X-ray diagnosis is particularly advantageous, because either the exposure latitude of the material is increased for the same degree of definition of detail, or the definition of detail can be improved with a harder material and the same exposure range.

For the usual X-ray exposure between intensifying foils, however, the ratio between the brightness of the front and back foils deviates from the value 1 to an extent which depends on the foils and exposure conditions which are used. This means that, depending on whether the film is disposed with its front or back facing the tube, a different color trend is obtained when the sensitivities of the emulsions on the front and back differ from one another. Furthermore, the use of a highly sensitive but non-contrasty emulsion causes an undesirable flattening in the initial part of the gradation curve. These disadvantages can be avoided to a certain degree by using ma- :erial of similar structure on the front and back, but this results in additional expense in the production of the naterial.

It has now been found that these disadvantages can as avoided if the exposure material used for the produc- IlOIl of radiographs by means of invisible radiation such 15 alpha, beta, gamma, and X-rays is a material which :omprises at least one silver halide emulsion layer con- :aining at least two color couplers for color forming delelopment which couple with the oxidation products of a primary aromatic amino developing agent with different reaction velocities to form dyes. It is found in this case :hat the color coupler which couples more quickly is the irst to react and that gradually as the concentration of his component decreases, the second color component also reacts with the excess of the oxidised developer.

By choice of different color couplers and different proportions, it is possible to produce a large number of :olor variations.

The colors of the dyes formed by coupling can be laried within wide limits. For example, for the reproiuction of highlights (light portions of the radiograph) ICC it is possible to use red or yellow dyes, while blue or magenta dye shades are used for the reproduction of the shadows (dark portions).

Suitable couplers with relatively high coupling speed are for instance those of the acylacetamide type. Such compounds correspond for instance to the following formula:

R.CO.CH .CO.NHR

3 (p-stearoylacetaminobenzoylacetamido) isophthalic acid 3 benzoylacetamino-4-[N-methyl-octadecylamino] benzoic acid 3-acetoacetamido-4-(N-methyloctadecylamino) benzoic acid 4-[p-stearoylaminobenzoylacetamido]-phenylglycine 4[m-stearoylaminobenzoylacetamido] benzoic acid 3-(stearoylacetamido)-isophthalic acid 4-(myristoyl acetamido)-phenylglycine 3-(p-benzoylacetaminobenzamido) 5 stearoylamino-ptoluene-sulphonic acid Examples of magenta color couplers of relatively high coupling speed are the following:

1 (4'phenoxy-3'-sulphophenyl) 3 heptadecyl-S-pyraz olone 1-( 3 '-carb oxyphenyl -3 -heptadecyl-5-pyrazolone 1- (4'-sulphophenyl) -3 -heptadecyl-5-pyrazolone 1-(3'-carboxyphenyl)-3-indecyl-5-pyrazolone 1 (2'-methoxy-5'-sulphophenyl)-3-(3'stearoyl aminophenyl)-5-pyrazolone 1-(3'-sulfomethylenephenyl)-3-heptadecyl-5-pyrazolone 1-( 3 'stearoylamino-S-sulfophenyl) -3 -methyl-5-pyrazolone Examples of cyan color couplers of relatively high coupling speed are the following:

1 hydroxy 2 naphthoyl 2' N methyloctadecyl amino-5' sulfoanilide 1-hydroxy-2-naphthoyl-4'-stearoylamino-2'-sulfoa.nilide 1 hydroxy 2 naphthoyl 4' oetadecylamino 7'- sulfonaphthalide 1 hydroxy 2 naphthoyl 4' octadecylamino 2'- sulfoanilide 1 hydroxy 2 naphthoyl 4' N methyldodecylamino- 3'-sulfoan.ilide Examples of color couplers with relatively low coupling speed are phenols and a-naphthols which contain replaceable groups in the coupling position (that is to say in para-position to the hydroxy group) such as sulfonic acid groups or halogen atoms, e.g. a chlorine or bromine. Further examples of such color couplers are the indazolones. Suitable cyan color couplers with relatively low coupling speed are for instance the following:

1 hydroxy 2 naphthoyl N octadecylamide 4 sulfonic acid 1 hydroxy 2 naphthoyl 3' octadecylamino 4- sulfoanilide 4 sulfonic acid 1 hydroxy 2 naphthoyl 3 octadecylamino 4'- carboxyanilide 4 sulfonic acid 1 hydroxy 2 naphthoyl 3 oleylamino 4' sulfoanilide 4 sulfonic acid 1 hydroxy 2 naphthoyl 3 abiethylamino 4' sulfoanilide 4 sulfonic acid 1 hydroxy 2 naph-thoyl 4' heptadecylamino 2'- sulfoanilide 4 sulfonic acid (The above color couplers are disclosed in British specification 701,039.)

The total amount of the above color couplers added to a silver halide emulsion of 40-60 g. silver content is about 5 to 25 g., preferably to 20 g. per kg. of emulsion. The relative amount of the color couplers may vary within wide limits; proportions by weight between 1: 10 and 10:1 have been found particularly suitable.

According to a further embodiment of the present invention the color coupler may be incorporated in a water permeable, water insoluble solvent as disclosed for instance in U.S. patent specifications 2,304,940 and 2,322,- 027 before they are added to the silver halide emulsion.

Example 1 velopment, bleaching and fixing, an image is obtained which has pink color shades at the light portions and blue color shades at the dark portions. For the processing of the film there may be used the ordinary color forming developing solutions containing a primary aromatic amino compound such as N-hydroxy-N-ethyl-p-amino-aniline as developing agent.

Example 2 120 cc. of a 5% solutionof a-stearyl-succionyl-5-aminoindazolone in aqueous sodium hydroxide solution with a final pH value of about 9, and 80 to 120 cc. of a 5% solution of 3-(p-stearoylarninobenzoylacetamido)-isophthalic. acid in aqueous sodium hydroxide solution with a final pH value of about 9, are added to 1 kg. of a highly sensitive silver halide emulsion with the conventional additives. The processing takes place as in Example 1 and yellow color tones are obtained at the lightly exposed areas and red color tones at the strongly exposed areas. It the yellow coupler is replaced by 4 g. of l-hydroxy-Z- naphthoyl 2' L N methyloctadecylamino 5 sulfoanilide there result radiographs which are cyan in the lightly exposed areas and magenta at the strongly exposed areas.

The above indazolone coupler is contained as follows: A solution of 5.2 g. of S-aminoindazolonehydrochloride (Berichte 75 (.1942), page 1107), and 9 g..ofioct-adec'enylsuccinic acid anhydride in 35 cc. of pyridine is refluxed for two, hours and thereafter added to a mixture of 350 cc. of water and 35 cc. of concentrated hydrochloric acid. The precipitate fonmed'is sucked off and washed with acetone and methanol.

Example 3 4 g. of 1-(4f-phenoxyphenyl-3-sulphonic acid)-3-heptadcyl-S-pyrazolone and 6 g. of 1-hydroxy-4-sul'pho-2 naphthoylamino-2'-methyl-stearylamino-5f-sulphonic acid are added'in the same way asrin Example 1 to 1 kg. of a highly sensitive silver halide emulsion with the usual additives and then processed as in Example 1. Red color tones are obtained in the highlights and blue color tones in the shadows.

The second coupler is obtained by treating l-hydroxy- 2 naphthoyl 2' N methyl octadecylamino 5- sulfoanilide with 10 cc. of concentrated sulfonic acid at 60 C. until the reaction product has become water soluble.

Example 4 4 g. of 1-(4'-sulfopheny1)-3-heptadecyl-5-pyrazolone and 6 g. of 1hydroxy-4-sulpho-2-naphthoyl-stearyl-amine are added in the same way as in Example 1 to 1 kg. of a highly sensitive emulsion with the usual additives and processed as in Example 1. Red color tones are obtained in the highlights and blue color tones in the shadows.

Example 5 12.5 g. of the cyan coupler disclosed in Exampled are added to 1 kg. of a highly sensitive silver halide emulsion. This emulsion is coated on a transparent film support to produce a layer of about 7,44 thickness. On this layer and on the backside of the support there are coated silver halide emulsions, which contain per kg. 5 g'. of the indazolone and 4 g. of the yellow coupler of Example 2. After exposure by means of X-rays this material is processed in the same manner as disclosed in Example 1. The radiograph is yellow in the areas of small exposure, red in the areas of medium exposure and black in the strongly exposed areas.

Example 6 A highly sensitive silver halide emulsion containing per kg. 6 g. of the indazolone and 6 g. of the yellow coupler of Example 2 is coated on a transparent film support to produce a layer of 0.015 mm. thickness. On the backside of said support there is coated the same emulsion containing per kg. 10 g. of the yellow coupler of Example 2 and 3 g. of the cyan coupler of Example 1 to produce a layer of- 0.015 mm. thickness. After exposure by means of X-rays this material is processed in the same manner as disclosed in Example 1. The radiograph obtained is yellow in the areas of small exposure, red in the areas of medium exposure and olive-green in the strongly exposed areas.

The materials of the present invention may also be processed to positive images by the reversal process according to well known practices.

I claim:

1. A process for the production of radiographs with invisible actinic rays which comprises exposing to said rays a silver halide emulsion layer containing at least two color couplers which couple at different reaction velocities with the oxidation products of the same color forming primary amine developed to form differently colored dye images, the coupler of higher coupling velocity being selected from the group consisting of acylacetamides, 5-pyrazolones, and alpha-'naphthols' which are not substituted in para-position to the phenolic hydroxy group; and the coupler of lower coupling velocity being an alphanaphthol which contains in para-position to the hydroxy group a substituent which is split off during development, said substituent being selected from the class of halogen atom and a sulfonic acid group, said different reaction velocities being such that development of said layer with said developer forms a color image in which the shadows have different color shades than the highlights, and processing said exposed material in such a developer to produce a radiograph having shadows with difierent color shades than the highlights.

2. A photographic material comprising a silver halide emulsion layer containing at' least two color couplers which couple at difierent reaction velocities with the oxidation products of the same primary amine color forming developer at exposed portions of the layer to form dye images of difierent color shades, the coupler of higher coupling velocity being selected from the group consisting of acylacetamides, 5-pyrazolones, and alphanaphthols which are not substituted in para-position to the phenolic hydroxy group; and the coupler of lower coupling velocity being an a'l-phanapthol which contains in para-position to the hydroxy group a substituent which is split off during development, said substituent being selected from the class of a halogen atom and a sulfonic acid group, said reaction velocities being sufiiciently different that after exposure, the development of said layer with such developer produces a color image having shadows with different color shades than the highlights.

References Cited in the file of this patent UNITED STATES PATENTS Murray et al May 23, 1939 Schneider et al J an. 9, 1940 Wilmanns et al Dec. 10, 1940 Slifkin Feb. 20, 1951 Slifikin Feb. 20, 1951 Fine June 30, 1953 Weller et a1. Sept. 21, 1954 Godowsky Jan. 4, 1955 Sanders et a1. May 21, 1957 FOREIGN PATENTS Great Britain July 25, 1949 UNITED STATES PATENT. OFFICE CERTIFICATE OF CORRECTION Patent No. 2 994 6lO August l 1961 Fritz Maus I It is hereby certified that error appears in the above numbered patent requiring correction and that the said Letters Patent should read as corrected below. 4

Column 2 line 42 for "*--indec yl read undecyl- -5 Column 3 line 5, for "abiethylamino-" read -abietyl- 7 amino 5 line 45, for "-stearyl-succionyb" read wctadeoenyl-succinoyl same column 3 line 6O for "contained," read obtained Signed and sealed this 3rd day of April 1962,

(SEAL) Attest:

ERNEST W. SWIDER Attesting Officer DAVID L. LADD Commissioner of Patents 

1. A PROCESS FOR THE PRODUCTION OF RADIOGRAPHS WITH INVISIBLE ACTINIC RAYS WHICH COMPRISES EXPOSING TO SAID RAYS A SILVER HALIDE EMULSION LAYER CONTAINING AT LEAST TWO COLOR COUPLERS WHICH COUPLE AT DIFFERENT REACTION VELOCITIES WITH THE OXIDATION PRODUCTS OF THE SAME COLOR FORMING PRIMARY AMINE DEVELOPED TO FORM DIFFERENTLY COLORED DYE IMAGES, THE COUPLER OF HIGHER COUPLING VELOCITY BEING SELECTED FROM THE GROUP CONSISTING OF ACYLACETAMIDES, 5-PYRAZOLONES, AND ALPHA-NAPHTHOLS WHICH ARE NOT SUBSTITUTED IN PARA-POSITION TO THE PHENOLIC HYDROXY GROUP, AND THE COUPLER OF LOWER COUPLING VELOCITY BEING AN ALPHANAPHTHOL WHICH CONTAINS IN PARA-POSITION TO THE HYDROXY GROUP A SUBSTITUENT WHICH IS SPLIT OFF DURING DEVELOPMENT, SAID SUBSTITUENT BEING SELECTED FROM THE CLASS OF HALOGEN ATOM AND A SULFONIC ACID GROUP, SAID DIFFERENT REACTION VELOCITIES BEING SUCH THAT DEVELOPMENT OF SAID LAYER WITH SAID DEVELOPER FORMS A COLOR IMAGE IN WHICH THE SHADOWS HAVE DIFFERENT COLOR SHADES THAN THE HIGHLIGHTS, AND PROCESSING SAID EXPOSED MATERIAL IN SUCH A DEVELOPER TO PRODUCE A RADIOGRAPH HAVING SHADOWS WITH DIFFERENT COLOR SHADES THAN THE HIGHLIGHTS. 